Arrangement at centerless grinding machines



9, 1950 s. E. A. THOMTE 2,520,228

ARRANGEMENT AT CENTERLESS GRINDING MACHINES Filed Feb. 19, 1947 2 Sheets-Sheet l fkrexfar 576w EVA Ara 7/70Mr We; w Yf @p'enfs Aug. 29, 1950 s. E. A THOMTE 2,520,228

ARRANGEMENT AT CENTERLESS GRINDING MACHINES FiledFeb. 19, 1947 2 Sheets-Sheet 2 fm endar 6'75 [kW/4m 77mm? {penis Patented Aug. 29, 1950 I ARRANGEMENT AT CENTERLESS GRINDING MACHINES Sten Erik Axel Thomte, Halmstad, Sweden, as-

signor to Aktiebolaget Malcus Holmquist,

Halmstad, Sweden Application February 19, 1947, Serial No. 729,523 In Sweden February 8, 1946 The present invention relates to improvements in centreless grinding machines.

The object of the invention is to effect a perfect (or practically complete) contact between the obliquely placed pressing roller and the work piece.

More specifically, the object of the invention is the arrangement of the tool holder in the dressing apparatus in a way that the dressing point of the diamond may be conveniently adjusted to vary the amount of its offset when the axis, of the pressing wheel is inclined relatively to the axis of the grinding wheel. The dressing diamond may thus be adjustably positioned at such a distance from a line passing through the centre of the diamond holder and parallel to the moving direction of the dressing slide, that the generatrix of the working surface of thepressing roller resulting from the dressing will begiven the curved shape required for attaining th perfect contact.

The invention relates to grinding machines in which the dressing slide as well as the pressing roller are adjustable independently of each other, in the embodiment hereinafter more specifically described, by means of micrometrical screws for the purpose of attainingthe desired exact curve shape of the generatrix of the working surface of the pressing roller in connection with the setting of the diamond.

The invention will be described more in detail in connection with the embodiment illustrated on the accompanying drawings. v

Fig. 1 illustrates a side view, partly insectional elevation of the pressing roller, the dressing slide and the dressing diamond and the adjusting means of the pressing roller as well as of the dressing slide, while Fig. 2 is a section taken on the line A-A of Fig. 1.

On the accompanying drawings l designates the machine stand on which the grinding disc and the bearing device of the disc (not shown) are placed and made in a manner known per se. The machine bed I also carries the pressing wheel carriage l6 slidable thereon in a direction across the center axes of the pressing wheel 2, the work 3, and the grinding wheel I5. On the carriage IE3 there is journalled the pressing carrier 4 tiltable about a pivot about an axis 2 i- 2l in the said direction and through the center 22 of the pressing wheel 2. The pressing wheel 2 is journalled in the conventional way on the pressing wheel carrier 4.

Through proper tilting of the pressing wheel carrier 4 about its pivot 20 the axis of the press- 1'Claim. ('Cl. 125-11) ing wheel can .be given the desired declination in relation to the grinding disc l5 and thereby also to the axis of the work piece placed on the support guide 5. For attaining an exact declination of the pressing roller 2 a micrometrical setting device 6 is provided by means of which the pressing wheel carrier 4 may be tilted about its pivot 20 and set at a desired angle relatively to the work piece 3. i

The pressing wheel carrier 4 has at its top and rigid therewith asupporting plate 23 shaped with a seating recess 24 and a longitudinal slot I2 traversing the seating recess. The supporting plate 23 supports above the dressing wheel 2 the dressing, apparatus comprising-a base portion 1, a bracket 21, and a dressing tool holder II.

The base'portion comprises downwardly projecting trunnion segments 28 adapted to be seated and rotated on the seating recess 24. The base portion is further provided with a guideway 29 on which a slide 30 provided at the underside of the bracket 2! may be displaced, by means of a hand wheel 8, generally parallel to the direction of. the axes of the pressing wheel and grinding wheel, in the position shown in Fig. 2, along axis 3I,3l.

In addition to this longitudinal displacement. the base portion 1 with the bracket and tool holder thereon is furthermore adapted to be swung by means of its trunnion segment seat about the center axis 9 of this seat by aid of another micrometrical setting device ID in such a manner that the longitudinal axis of the dressing slide 30 can be set accurately at the desired angle in relation to the shaft of the pressing roller 2.

In the bracket 21 there is further vertically arranged a rotatable and longitudinally movable diamond holder ll within a sleeve 32 of bracket 21 and protruding through slot l2 in the supporting plate 4. The dressing diamond l3 at the lower end of the diamond holder II is secured to the holder at a point radially spaced from the axis of the tool holder and thus is eccentrically arranged in relation to the centre of same in such a manner that the diamond l3 by the rotation of the diamond holder H can be set at a variable distance from a line passing through the centre of the diamond holder and parallel to the longitudinal moving direction of the dressing slide 30. The raising or lowering respectively of the diamond holder II and thereby of the diamond I3 is efiected by means of a micrometrical screw I 4, while the rotation of the diamond holder H may be obtained by the use of a special diamond setting tool (not shown).

in a manner known per se, so that the axis of the.

gauge will be located above or below a plane passing through the shaftaofithe:grindingadisor l5 and the shaft of the pressing roller 2 wiierrv these shafts are parallel. Thereafter. theflshaftn of the pressing roller 2 is obliquely,placedlacertain angle to the above mentioned plane, said angle in conjunction with the diameter and the rotation speed of the pressing-roller-2 dtermin=- ing the peripheral speed of the Work piece: angular setting is effected by aid of the micromet, rical setting device 5 and will probably amount to a declination angle of about 2 to 3. U

Secondly; tlle'dressingtslide 3D'1is'set atr'a; cer= tain'angle in relation totheshaftoftliezpressing roller 2 lb; 'aid or" 'tlieiother' micrometrical setting device I 0, which anglaatthe-chosenexample ac;- cording to theinvention is "somewhatsmallerthan. the declination" angle of thepressing roller" 21 Thereafter 'by turning ofthe diamond holder I] the dressing diamond ISissetatia certain dis-s tance from a linep assing thrcughtthacentre of :thea diamond holder and 'parallelly to the mov.- ing direction offtne2di'essing'slide 30'." This dis'= tance should'at: the chosen example Vamount"toi about"8* mm: in" the: case that the 4 centre .heig'ht ofrthe :work piece above and" below respectively; of the-above mentioned plane through;the'sl'iaits of the grinding? discahd of thelpressing roller amounts: to 'for instance" 9i5"mm: The'n'ow indie cated"setting-values; ofthe chosenworlipiece are obtainedby-followinga table appertaining'to'tlie'; machine. 7 a v p e Afterthe above-mentioned settingsjhe dress;- ing,;ofthe pressingrollntakes place bymeans' of" the: diamond in a manner" known per;se;j whereby the; generatrix of the Working surfaceof' the pressing 'roller 2 obtainsjust" the" hyper? bola shape that assures thevperfect .(or practicalli complete) contact" b'etweem the obliquely set. pressingrolleitand the work piece.

Howeveiyitis evidentrthat'if a' workpiece having another-diameter". has to be groundflater, on a'new settingancfdtessing takes placev according to'thevabove mentioned'setting table;

' The" invention issof' course not limited to the m 4v varied in many different ways within the scope of the invention.

Having now particularly described the nature of my invention and the manner of its Operation what I claim is:

Apparatus ,for. dressing; the peripheral surface ofthe pressing wheel of iazcenterlessgrinding machine of the type wherein the machine bed carries the pressing wheel carriage slidable thereon in a direction across the center of the pressing wheel; th'e work-and the grinding Wheel, and the pressing wheel carrier is journalled on said carriage-;-tiltable.:about,an axis in the said direction and: through the; center of said pressing wheel andxsaid: pressingwheel carrier has a supporting plate rigid therewith for mounting thereon said dressing; apparatus; aseating recess and a longitudi'nal slotbeing shaped in said supporting plate, said:- dressing apparatus comprising a base portion, a bracket, and a dressing tool holder, said slot traversing saidseatingrecess, said base portion comprising downwardly. projecting-1 trunnion segments adapted. ta e seated and. rotated on saidiseatingrecess,,a-guideway; disposed on saidtrunnion segments,v said;b'racket..having a --slide saidfbaselportion forjangularly displacing; about 4 said'seatingrecessrand;relatively tosaidsupport-- embodiment. illustratedand described butcarr be" 55 ing plate; said. base. portion.v with 2 said bracket thereon";saidjbracketlhaving a .bore,- a sleeve-dis posed in saidl bore, ancLsaid tool-l holder; in :said

sleeve; said tool? holder. being adapted thereby" to g be displaced: lengthwise, and.- rotationall in; said i bracket, said toollll'olderl having 1 means forsecuringthe dressing diamondat said holder at: a point-radially spacedtfrom the axis of said, tool.

holder; thereby, by. displacement oil said tool holder lengthwise of 'saidb'racket to extendsaidtool holder through-.saidlslotand bring saiddiam'ond into contact with said peripheral surface. andby rotation ofisaidltool 'holderinsaidbrackeh toivarythe *amou'ntoffofiset of the dressing point.

STEN THOMTE."

' REFERENCES CITED The following, references, are-of record i in n the file of'this' patent:

Haasl- Nov. 27, 1934 

